On Tue, Aug 16, 2011 at 9:47 AM, Marvin Addison <[email protected]>wrote:
> > what is the Memcache solution and do you have a setup guide? > > See https://wiki.jasig.org/display/CASUM/MemcacheTicketRegistry. I'll > discuss briefly what's _not_ in the manual. I think there's some > misinformation in the community, borne out in list discussions and > other venues, about the need for the repcache patches to memcached for > clustering. I think repcache is absolutely unnecessary based on the > failure mode of memcached. Consider a memcached cluster of 3 nodes, > all noted in the CAS configuration. The Java memcached client will > calculate a key and store it on one node. If that node goes down, the > client will attempt to retrieve the key from the dead node and fail, > returning an empty value. That will appear to CAS and ultimately the > user that he or she is unauthenticated and will simply need to > reauthenticate. Upon reauthentication the client will know that there > are only two nodes remaining, and calculate a new key that will be > stored on one of the two available nodes and proceed as normal. That > is a _very_ graceful failure mode in my opinion, and there's no need > for anything additional like repcached. > It really depends on your needs. You may feel that its acceptable to force them to log back in if a node goes down, others may not. This is why we have a number of these backing mechanisms, you find the one that matches your expertise and meets your availability requirements. However, as you note, using repcached is optional, and just provides an extra level of redundancy if you want to apply the patch. (we did at Rutgers) Cheers, Scott > > > Is one solution favourable over another? > > Most folks choose based on experience with a particular technology. > We use JpaTicketRegistry on PostgreSQL in production, but I'd be happy > to switch to memcached if needed. I personally think Terracotta, > JBossCache, and Infinispan are interesting technologies that are > overkill for CAS. The complexity is not worth the benefits. That is > absolutely a personal opinion and lots of folks would disagree. > > M > > -- > You are currently subscribed to [email protected] as: > [email protected] > To unsubscribe, change settings or access archives, see > http://www.ja-sig.org/wiki/display/JSG/cas-user > > -- You are currently subscribed to [email protected] as: [email protected] To unsubscribe, change settings or access archives, see http://www.ja-sig.org/wiki/display/JSG/cas-user
